The present invention is directed to improving electrolytic cells with vertical electrodes, more particularly cells equipped with metal anodes and intended for example for the production of alkali metal chlorate or hypochlorite, or for the production of chlorine.
It is known to employ metal anodes in cells for the electrolysis of aqueous solutions of alkali metal halides. These anodes are usually made up of plates of a film-forming metal or an alloy of a film-forming metal covered, at least partially, with an active coating which catalyses the discharge of halide ions.
Until now, the development of cells with metal anodes has been checked by the difficulties encountered in fixing the anodes within the cell and in connecting them to a current lead-in.
In British Pat. No. 1,160,999 applied for on May 2, 1967 in the name of IMPERIAL METAL INDUSTRIES (KYNOCH)LIMITED, there is proposed an anode assembly for an electrolytic cell, wherein substantially vertical and parallel anode plates are clamped between horizontal beams, made of an electrically non-conducting material, which form the base of the cell, and the anodes are connected to one or more current lead-in bus-bars extending beneath the beams. The pressure of the beams on the anode plates is sufficient to support the anodes and the bus-bars connected to them, and to ensure the fluid-tightness of the base of the cell.
This known anode assembly has the advantage of permitting quick and easy assembly and dismantling of the anodes in the cell.
A major disadvantage of this known anode assembly nevertheless resides in the difficulty of ensuring effective and durable fluid-tightness between the anode plates and the beams forming the base of the cell. The sealing joints interposed between the anode plates and the beams are in fact strongly acted upon by the large hydrostatic pressure, the high temperature and the corrosive nature of the electrolyte. These joints must be greatly compressed, beyond their elastic limit, so as on the one hand to prevent their expulsion under the effect of the hydrostatic pressure and on the other hand to prevent sliding of the anodes between the beams.